1. Field of the Invention
The present invention relates to a packaged beverage having a high concentration of catechins.
2. Related Art
Now, the market of foods containing tea leaves as a raw material such as canned beverages and instant drinks is massive. It is reported that catechins contained in tea drinks such as green tea, black tea and Oolong tea have physiological usefulness such as cholesterol-level-rise suppressive action (Japanese Patent Laid-Open No. 156614/1985), α-amylase activity inhibitory action (Japanese Patent Laid-Open No. 133928/1991), blood-sugar-level-rise inhibitory action (Japanese Patent Laid-Open No. 253918/1992), arteriosclerosis preventive action (Japanese Patent Laid-Open No. 352726/1992), antioxidative action (Japanese Patent Publication No. 44234/1989), antibacterial action (Japanese Patent Laid-Open No. 276562/1990), blood-pressure-rise suppressive action and enzymatic activity inhibitory action (Japanese Patent Laid-Open No. 133928/1991), antitumor action (Japanese Patent Laid-Open No. 277628/1988) and mutation suppressive action.
In order to allow catechins to exhibit their physiological action more effectively, an increase in the intake amount of catechins is necessary. For this purpose, a beverage form facilitating intake of a large amount of catechins is desired from the viewpoint of preference and marketability. Intake of a large amount of catechins is however accompanied with such drawbacks that bitterness or astringency peculiar to them becomes an obstacle to it, they tend to impart the resulting beverage with a turbid appearance, they cause a marked change in color tone after long-term storage in the package, and a deterioration in taste upon retorting is negligible. These drawbacks damage the commodity value of the beverage. With these problems in view, improvement and investigation are under way.
If the beverage contains an increased amount of catechins, more effective absorption of them in the body will not only increase their utilizing degree but also contribute to the health promotion. It is known (“Kagaku to Seibutsu, 38, 2, 104–114(2000)”) that with regards to absorption in the body, that is, pathway for the transfer of catechins to the blood, a very small portion of catechins is absorbed from the digestive tract; some of the thus absorbed catechins are subjected to conjugation reaction in the mucoepithelial cells, transported to the liver through portal veins, and conjugated further; with some in the conjugated form and some in the free form, the catechins enter in the blood stream, and transferred to the peripheral tissue; and with some in the form contained in a bile secreted from the liver, the catechins are injected into the duodenum and after enterohepatic circulation, transferred to the kidney and then at last, secreted into urea.
With health-oriented trend and prevalence of PET beverages in recent years, the consumption amount of green tea is on increase among young people. Development of a beverage permitting positive use of physiologically active catechins in the body is desirable from the viewpoint of health enhancement.